The same applies to sales, promotions, vouchers, gifts.
They are all ways to reduce the effective price. The customer calculates the money value of these benefits and deducts them from the price.
Establish a "pattern" of severe retaliation against challengers to "communicate commitment" to resist efforts to win market share. - Again, this retaliation can take a myriad of forms: malicious advertising, a media campaign, adverse legislation, blocking distribution channels, staging a hostile bid in the stock exchange just in order to disrupt the proper and orderly management of the competitor. Anything which derails the competitor whenever he makes a headway, gains a larger market share, launches a new product - can be construed as a "pattern of retaliation".
Maintain excess capacity to be used for "fighting" purposes to discipline ambitious rivals. - Such excess capacity could belong to the offending firm or - through cartel or other arrangements - to a group of offending firms.
Publicize one's "commitment to resist entry" into the market.
Publicize the fact that one has a "monitoring system" to detect any aggressive acts of competitors.
Announce in advance "market share targets" to intimidate competitors into yielding their market share.
Proliferate Brand Names Contract with customers to "meet or match all price cuts (offered by the competition)" thus denying rivals any hope of growth through price competition.
Secure a big enough market share to "corner" the "learning curve," thus denying rivals an opportunity to become efficient. - Efficiency is gained by an increase in market share. Such an increase leads to new demands imposed by the market, to modernization, innovation, the introduction of new management techniques (example: Just In Time inventory management), joint ventures, training of personnel, technology transfers, development of proprietary intellectual property and so on. Deprived of a growing market share - the competitor will not feel pressurized to learn and to better itself. In due time, it will dwindle and die.
Acquire a wall of "defensive" patents to deny competitors access to the latest technology. "Harvest" market position in a no-growth industry by raising prices, lowering quality, and stopping all investment and advertising in it.